FileTaylor Mays (background) and his fellow USC defenders have struggles the past two games, against Notre Dame and Oregon State.LOS ANGELES — In his first three years at USC, senior safety Taylor Mays played on some of the strongest defenses the fabled football school has ever produced.

For a while, this season's Trojans defense seemed ready to follow suit. But less-then-stellar performances the past two weeks have left some wondering if the Trojans can handle Oregon's high-powered spread offense when the teams meet Saturday in a Pacific-10 Conference showdown at Autzen Stadium.

"We slid a little the last two games, but we got the wins," said Mays, a first-team All-America pick last season. "But we've got to play better."

The bar is ultra-high for defense at USC, where coach Pete Carroll — whose résumé includes six seasons as an NFL defensive coordinator — annually puts together units stocked with athletic, NFL-bound blue-chippers.

Mays, a starter since the second game of his freshman season in 2006, has played on defenses from which 15 players were taken in the NFL draft, including eight in the first two rounds.

The 2006 unit ranked No. 21 nationally in total defense at 391.9 yards and No. 11 in scoring at 15.2. In 2007, the Trojans were No. 2 in both total defense (273.2 yards) and scoring (16.0).

Last season's defense set the bar even higher. It ranked No. 1 nationally in scoring (8.9) and was second in total defense (221.8), with averages in both categories that were the best at USC in 41 years. Eight players from that unit were drafted.

Mays could have been the ninth but chose to return for his senior season. There were changes to contend with as defense coordinator Nick Holt left for Washington.

Carroll promoted Rocky Seto, who has been on USC's staff for 11 seasons, to defensive coordinator, and with its usual slew of blue-chippers among eight new starters, the defense didn't seem to miss a beat early. In the Trojans' first five games, they held opponents to 249 yards and 8.6 points per game.

But in wins over Notre Dame and Oregon State the past two weeks, the Trojans gave up 795 yards and 63 points. USC had early leads in both games and seemed headed for easy wins, but the Irish and Beavers made second-half rallies that left the outcomes in doubt until the end.

"My evaluation is, we haven't done very well," Carroll said. "Been really susceptible to them throwing the football. Being ahead didn't help us any. We didn't play well with the lead."

Notre Dame quarterback Jimmy Clausen threw for 260 yards and two touchdowns against the Trojans, and OSU's Sean Canfield for 329 yards and two scores.

"Both of the first halves of the games, the mix of the run and pass wasn't a big issue for us," Carroll said. "But when the team decided they needed to throw the football to win, they did very well."

Defensive tackle Armond Armstead said that while Clausen was sensational, the Trojans deserve the blame for Canfield completing 30 of 43 passes against them.

"I feel like sometimes (Notre Dame) just made plays that were perfect plays that they had to make throughout the game," he said. "Oregon State, I felt like our defense did struggle a little bit, but that was for different reasons, because we just made mistakes as a defensive unit. It wasn't anything that they did to us."

To Mays, the Trojans' main problem is that they didn't maintain the swagger that has characterized USC's defenses.

"I don't know if it's assignments as it is an attitude," he said. "We've got to dominate every time we step on the field."

After the past two weeks, it might seem USC would be thankful to face an Oregon team that ranks last in the Pac-10 in passing yards. But the Trojans say Oregon's multitude of options, especially with a dangerous runner at quarterback in Jeremiah Masoli, will test them.

"Your athleticism helps when you play football, but when you play a team with a lot of options, you have to play a lot smarter," Armstead said. "You can't just close when you see your blocker go down. You have to realize that (Masoli) might fake the handoff and take the ball and go the other way."

Mays, who grew up near Seattle, has roots in Oregon — his father, Stafford, played at Mt. Hood Community College, his mother, Laurie, was raised in Portland, and his grandparents live in Boring.

But he has never won in the state, with the Trojans losing at Oregon State in 2006 and 2008 and at Oregon in 2007. He says he can't explain the losing streak, but knows what he and USC's defense must do to end it — live up to the high standard set by previous USC defenses.

"We've got the potential to be the best," he said. "We've been the best sometimes, and we haven't been as good other times. We just have to be more consistent. We've got to bring it every time we step on the field, bring it for four quarters every game."